The system of short period meteor streams

1974 ◽  
Vol 22 ◽  
pp. 269-281 ◽  
Author(s):  
B. A. Lindblad

AbstractThe orbital characteristics of precisely reduced photographic meteors were studied. Most photographic meteors move in short period, direct orbits with orbital periods inbetween those of Jupiter and Mars. Practically no meteors have (Orbital periods coincident with those of the planets Jupiter, Mars and Earth.A search among all precisely reduced, photographic meteors revealed a number of new – or previously not well studied – meteor streams. For 18 short period meteor streams the scatter in the orbital elements 1/a,πand Ω was studied. An almost linear relation was found between the mean orbital energy of a meteor stream (– 1/a) and the standard deviation σ(1/a), indicating a progressive increase in the orbital scatter with decreasing mean distance to the sun. An index of mean meteoroid density was computed for 11 of the short period streams. The mean density increases with decreasing semi-major axis.The results are interpreted as indicating that the short period meteor streams are initially formed in orbits with periods slightly shorter than Jupiter’s. As the streams gradually drift inwards towards the sun under the influence of various drag forces the individual stream members spread out and only the high density, resistant meteors still remain, or can be recognized, as stream members.

1985 ◽  
Vol 83 ◽  
pp. 179-180
Author(s):  
Cl. Froeschlé

We investigated the orbital evolution of Quadrantid-like meteor streams situated in the vicinity of the 2/1 resonance with Jupiter. For the starting orbital elements we took the values of the orbital elements of the Quadrantid meteor stream except for the semi-major axis which was varied between a = 3.22 and a = 3.34 AU. We considered these meteor streams as a ring and we investigated the resonant effect on the dispersion of this ring over a period of 13 000 years. Only gravitational forces due to the Sun and due to Jupiter were taken into account.


1968 ◽  
Vol 33 ◽  
pp. 217-235 ◽  
Author(s):  
Ľ. Kresák

The relation of physical characteristics of meteors to their orbital elements is investigated using Harvard Super-Schmidt data. A set of characteristic indices is defined, allowing for the effects of geocentric velocity, angle of incidence, magnitude and mass, wherever a correction appears appropriate according to the correlations found by Jacchia et al. (1967). The medians for representative meteor samples are plotted in the semi-major axis/eccentricity diagram and the distribution of each parameter is derived. Although the differences are moderate compared to the measuring errors, six regions of different nature can be distinguished.The existence of two families of asteroidal meteors is indicated, one of them brought to crossing with the Earth's orbit by drag effects and the other by collision effects in the main asteroid belt. These meteors are characterized by low and uniform beginning heights, high fragmentation, low ablation, low deceleration, and bright wakes. A direct counterpart to this is represented by meteors moving in short-period orbits of higher eccentricity and shorter perihelion distance, which bear resemblance to the long-period and retrograde cometary meteors. Meteors with perihelion distances of less than 0·15 AU tend to resemble the bona fide asteroidal meteors by a progressive increase of fragmentation and decrease of reduced beginning heights and decelerations as the perihelion approaches the Sun. This is attributed to the selective destruction effects of solar radiation.With the exception of the Draconids, the mean characteristics of meteor showers agree well with those of sporadic meteors moving in similar orbits. It is suggested that the Draconid stream includes a broad variety of meteoric material and that the two peculiar Super-Schmidt meteors on record represent only the less resistive, short-lived component which has already been eliminated from the other showers.


Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 183
Author(s):  
Yongjie Liu ◽  
Yu Jiang ◽  
Hengnian Li ◽  
Hui Zhang

This paper intends to show some special types of orbits around Jupiter based on the mean element theory, including stationary orbits, sun-synchronous orbits, orbits at the critical inclination, and repeating ground track orbits. A gravity model concerning only the perturbations of J2 and J4 terms is used here. Compared with special orbits around the Earth, the orbit dynamics differ greatly: (1) There do not exist longitude drifts on stationary orbits due to non-spherical gravity since only J2 and J4 terms are taken into account in the gravity model. All points on stationary orbits are degenerate equilibrium points. Moreover, the satellite will oscillate in the radial and North-South directions after a sufficiently small perturbation of stationary orbits. (2) The inclinations of sun-synchronous orbits are always bigger than 90 degrees, but smaller than those for satellites around the Earth. (3) The critical inclinations are no-longer independent of the semi-major axis and eccentricity of the orbits. The results show that if the eccentricity is small, the critical inclinations will decrease as the altitudes of orbits increase; if the eccentricity is larger, the critical inclinations will increase as the altitudes of orbits increase. (4) The inclinations of repeating ground track orbits are monotonically increasing rapidly with respect to the altitudes of orbits.


Author(s):  
Jorge Peñarrubia

Abstract This paper uses statistical and N-body methods to explore a new mechanism to form binary stars with extremely large separations (≳ 0.1 pc), whose origin is poorly understood. Here, ultra-wide binaries arise via chance entrapment of unrelated stars in tidal streams of disrupting clusters. It is shown that (i) the formation of ultra-wide binaries is not limited to the lifetime of a cluster, but continues after the progenitor is fully disrupted, (ii) the formation rate is proportional to the local phase-space density of the tidal tails, (iii) the semimajor axis distribution scales as p(a)da ∼ a1/2da at a ≪ D, where D is the mean interstellar distance, and (vi) the eccentricity distribution is close to thermal, p(e)de = 2ede. Owing to their low binding energies, ultra-wide binaries can be disrupted by both the smooth tidal field and passing substructures. The time-scale on which tidal fluctuations dominate over the mean field is inversely proportional to the local density of compact substructures. Monte-Carlo experiments show that binaries subject to tidal evaporation follow p(a)da ∼ a−1da at a ≳ apeak, known as Öpik’s law, with a peak semi-major axis that contracts with time as apeak ∼ t−3/4. In contrast, a smooth Galactic potential introduces a sharp truncation at the tidal radius, p(a) ∼ 0 at a ≳ rt. The scaling relations of young clusters suggest that most ultra-wide binaries arise from the disruption of low-mass systems. Streams of globular clusters may be the birthplace of hundreds of ultra-wide binaries, making them ideal laboratories to probe clumpiness in the Galactic halo.


1971 ◽  
Vol 43 ◽  
pp. 675-695 ◽  
Author(s):  
A. B. Severny

In an attempt to summarize the present knowledge on the general magnetic field (gmf) of the Sun we pointed out the fine structure and the statistical nature of the gmf as one of its most important properties. The dipole-like behaviour of the mean polar field strengths is combined sometimes (since 1964) with a bias of the S-polarity flux for both poles. Highly uneven distribution of gmf with latitude and longitude, the disappearance of gmf at the South pole for months, and short period, almost synchronous at both poles, variations in the sign of gmf are pointed out. The fluctuations with time of the mean magnetic field of the Sun seen as a star (as well as mf at different latitudes) shows periodicity connected with the rotation of the Sun and very close agreement with the fluctuations of the interplanetary field (sector structure). The effect of faster rotation of N-polarities as compared with S-polarities as well as the bias of mean solar as well as interplanetary S-polarity fields are also pointed out. The possibility of short time-scale (hours) intrinsic changes in the local pattern of gmf is demonstrated.


1991 ◽  
Vol 126 ◽  
pp. 229-234
Author(s):  
H.U. Keller ◽  
K. Richter

Comets constitute an important source for the zodiacal dust cloud. Mainly large particles are contributed because the smaller particles are emitted into hyperbolic orbits relative to the sun. Radiation pressure force reduces the effective solar gravitational attraction. Information about large cometary particles can be derived from a variety of sources requiring quite different observational techniques. Many distinct meteor streams are connected to orbits of short period comets. These streams contain large dust particles that are very little influenced by radiation pressure force. In some cases such as the η Aquarids and Orionids connected to comet Halley the total mass and the age of the meteors have been derived (Hughes, 1987; Hajduk, 1987). The mass of the streams is 5 to 10 times larger than the present mass of the nucleus and their lifetime corresponds to 2000 to 3000 orbital periods. Visible meteors are typically 10−2g and more of centimetre size.


2015 ◽  
Vol 112 (14) ◽  
pp. 4214-4217 ◽  
Author(s):  
Konstantin Batygin ◽  
Greg Laughlin

The statistics of extrasolar planetary systems indicate that the default mode of planet formation generates planets with orbital periods shorter than 100 days and masses substantially exceeding that of the Earth. When viewed in this context, the Solar System is unusual. Here, we present simulations which show that a popular formation scenario for Jupiter and Saturn, in which Jupiter migrates inward from a > 5 astronomical units (AU) to a ≈ 1.5 AU before reversing direction, can explain the low overall mass of the Solar System’s terrestrial planets, as well as the absence of planets with a < 0.4 AU. Jupiter’s inward migration entrained s ≳ 10−100 km planetesimals into low-order mean motion resonances, shepherding and exciting their orbits. The resulting collisional cascade generated a planetesimal disk that, evolving under gas drag, would have driven any preexisting short-period planets into the Sun. In this scenario, the Solar System’s terrestrial planets formed from gas-starved mass-depleted debris that remained after the primary period of dynamical evolution.


2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Tanmay Kumar Poddar ◽  
Subhendra Mohanty ◽  
Soumya Jana

AbstractThe standard model leptons can be gauged in an anomaly free way by three possible gauge symmetries namely $${L_e-L_\mu }$$ L e - L μ , $${L_e-L_\tau }$$ L e - L τ , and $${L_\mu -L_\tau }$$ L μ - L τ . Of these, $${L_e-L_\mu }$$ L e - L μ and $${L_e-L_\tau }$$ L e - L τ forces can mediate between the Sun and the planets and change the perihelion precession of planetary orbits. It is well known that a deviation from the $$1/r^2$$ 1 / r 2 Newtonian force can give rise to a perihelion advancement in the planetary orbit, for instance, as in the well known case of Einstein’s gravity (GR) which was tested from the observation of the perihelion advancement of the Mercury. We consider the long range Yukawa potential which arises between the Sun and the planets if the mass of the gauge boson is $$M_{Z^{\prime }}\le \mathcal {O}(10^{-19})\mathrm {eV}$$ M Z ′ ≤ O ( 10 - 19 ) eV . We derive the formula of perihelion advancement for Yukawa type fifth force due to the mediation of such $$U(1)_{L_e-L_{\mu ,\tau }}$$ U ( 1 ) L e - L μ , τ gauge bosons. The perihelion advancement for Yukawa potential is proportional to the square of the semi major axis of the orbit for small $$M_{Z^{\prime }}$$ M Z ′ , unlike GR where it is largest for the nearest planet. For higher values of $$M_{Z^{\prime }}$$ M Z ′ , an exponential suppression of the perihelion advancement occurs. We take the observational limits for all planets for which the perihelion advancement is measured and we obtain the upper bound on the gauge boson coupling g for all the planets. The Mars gives the stronger bound on g for the mass range $$\le 10^{-19}\mathrm {eV}$$ ≤ 10 - 19 eV and we obtain the exclusion plot. This mass range of gauge boson can be a possible candidate of fuzzy dark matter whose effect can therefore be observed in the precession measurement of the planetary orbits.


Author(s):  
Nathalie Deruelle ◽  
Jean-Philippe Uzan

This chapter considers Newton’s 1665 explanations of the dynamics in the laws governing the motion of a planet around the Sun, which were established by Johannes Kepler in 1618. The first law states that the motion is planar and the trajectories are ellipses. The second states that the area swept out by the radius vector per unit time is constant. Finally, the cube of the semi-major axis a is proportional to the square of the period P, a3 = (const)P2. The chapter begins with the reduced equations of motion before turning to the ellipses of Kepler. It then illustrates the Kepler problem in the Lagrangian formalism, as well as central forces.


1978 ◽  
Vol 41 ◽  
pp. 15-32 ◽  
Author(s):  
L. Duriez

AbstractIn order to improve the determination of the mixed terms in classical theories, we show how these terms may be derived from a general theory developed with the same variables (of a keplerian nature). We find that the general theory of the first order in the masses already allows us to develop the mixed terms which appear at the second order in the classical theory. We also show that a part of the constant perturbation of the semi-major axis introduced in the classical theory is present in the general theory as very long-period terms; by developing these terms in powers of time, they would be equivalent to the appearance of very small secular terms (in t, t2, …) in the perturbation of the semi-major axes from the second order in the masses. The short period terms of the classical theory are found the same in the general theory, but without the numerical substitution of the values of the variables.


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